We conducted a double-blind, placebo-controlled, prospective, randomized study to assess the effects of tretinoin pretreatment on healing after trichloroacetic acid (TCA) chemical peel. Sixteen male patients (mean age, 67 years) with actinically damaged skin were treated daily with 0.1% tretinoin and placebo creams to the left and right halves of the face and the left and right forearms and hands, respectively, for 14 days prior to the 35% TCA peel. We subjectively noted that during the peel, "frosting" was more pronounced and uniform and occurred earlier in tretinoin-pretreated skin in 94% of the patients. Healed skin was measured planimetrically, and the healed area was determined with point stereology. Regardless of pretreatment, the face healed twice as fast as the forearm or hand. In all regions, the mean area healed was significantly greater in skin that had been pretreated with tretinoin. The differences between tretinoin and placebo, respectively, in healed skin were maximal after 5 days for the face (68% vs 52%), after 11 days for the forearms (72% vs 24%), and after 9 days for the hands (61% vs 29%). After 7 days, 75% of the tretinoin-pretreated hemifaces were completely healed, as opposed to 31% of the placebo-pretreated hemifaces. By visual inspection, we could not appreciate a cosmetic difference between tretinoin- and placebo-pretreated skin 2 weeks and 3 months after the TCA peel. We conclude that 0.1% tretinoin pretreatment for 2 weeks prior to the TCA peel will significantly speed healing, which may result in greater patient satisfaction. Patients presently being treated with tretinoin who later undergo a TCA peel might be expected to have similar results.